Have you loaded a different fuel mapping or checked the a/f ratio, ect...? These modern fuel injected bikes are not like old hot-rods where you just open up the exhaust and let it go. Unless done somewhat properly, you might have done more harm than good to the performance. I also agree somewhat with Optima on the appearance. You did a great job machining the cones and then painted it that nasty black. Clean the paint off the machined parts and wrap the sheet metal with carbon fiber if you want black.

Stock map works fine. Does it snap crackle and pop like a danmoto? NO. Stock map has some extra room in it.I do have an O2 sensor bung welded in and the setup for checking it. Don't see the need for it.As to appearances there is a lot you can do but the first issue to me is sound (tone) and volume of sound. This is a new internal design. Not bad but still too loud for me. I am working on another set of cans with my original and quieter design. Did this on my zzr 600 so I have an idea of what to expect. I'll mig weld it this time. Finally found SS wire. So it will be SS natural finish.

Sounds good. Welding's a great skill and handy to know. Don't get me wrong - I wasn't trying to rag on your work, just that after seeing your preliminary work, the end-result was sort of a let down. Looks like you are not finished though, I'm confident you'll end up with a sucessful project and look forward to seeing the end-product! With the outrageous prices of aftermarket cans/pipes, who knows, you might be able to make a few side bucks.

Yes i know its a work in progress. I want to get the right sound then go from there. Original style should be the quietest I can get with the size of the cans. Next maybe gut the stockers and rework internals. This would be good for peeps living in sound nazi areas. Cans are quiet with low throttle and sound off up in the revs. Stealth cans.

What is the diameter of the inlet and outlet? from the pictures it looks like quiet the bottle neck at the end. You always want to take the path of least resistance, it seems like your adding more back pressure. But then again I am assuming of the original picture.

Pipe is 1 1/4" OD which is about right for 337 cc's. if you don't know what size works with engine CC's look it up. Or measure the dia of the new 2013 street exhaust. Its a single. Or go to a bike shop and measure the dia of the exhausts on a 1000 cc bike with duals. Why are they small? There is a pipe size for engine size that relates to where the power band maxes out. Going up in size raises the rpm range and smaller lowers it. Or cut open the stockers and look at the small tubes that the gases are forced thru which is the most restricted point. If you don't want to do that just wait a while. After i'm done with the current project I will do just that and post the pics.